SkelRad A Midterm

Question 1

What germ layer is bone derived from?

Answer 1

mesoderm

Question 2

Diaphysis

Answer 2

primary center of ossification

Question 3

epiphysis

Answer 3

secondary center of ossification

Question 4

apophysis

Answer 4

secondary growth centers
a protuberance
functions as the attachment site for ligaments and tendons

Question 5

Enthesis

Answer 5

site of attachment of tendons and ligaments
highly vascularized
high metabolic activity

Question 6

What are the four functions of periosteum

Answer 6

attaches to the cortex via sharpey’s fibers
maintains caliber of bone by appositional bone growth
provies a transitional zone of attachment for muscles, ligament, and tendons
serves as a source of vascular perfusion for the outer third of the cortex

Question 7

5 zones of the growth plate:

Answer 7

metaphysis
zone of degeneration
zone of hypertrophy
zone of proliferation
resting cartilage

Question 8

Resting cartilage

Answer 8

attaches growth plate to epiphysis

if injured, growth stops

Question 9

zone of proliferation

Answer 9

where bone is lengthened due to active growth of chondrocytes
if cells die, growth stops

Question 10

zone of hypertrophy

Answer 10

chondrocytes mature
no active growth
weakest portion of the plate
site of salter-harris fractures

Question 11

zone of degeneration

Answer 11

aka zone of ossification
site of dying chrondrocytes, ossification starting
attaches growth plate to metaphysis

Question 12

What type of bone marrow is hematopoietically active

Answer 12

Red marrow

Question 13

what type of bone marrow increases with age

Answer 13

yellow (fatty) marrow

Question 14

how are calcium and phosphorous levels related?

Answer 14

inversely

Question 15

what are the two main functions of parathormone

Answer 15

stimulate and control the rate of bone remodeling

influence mechanisms governing control of plasma level calcium

Question 16

Two direct effects of parathormone

Answer 16

stimulates ca++ absorption from glomerular fluid in kidneys

promotes osteoclastic resorption in the bone

Question 17

indirect effect of parathormone

Answer 17

influences rate of calcium absorption in the intestine

Question 18

functions of vitamin d

Answer 18

regulates intestinal mineral absorption

maintains skeletal growth and mineralization

Question 19

Vitamin D

Answer 19

key hormone responsible for calcium absorption from the diet

Question 20

Categories of bone disease

Answer 20

"cat bites"
congenital
arthritis
trauma
blood (hematological)
infection
tumor
endocrine, nutritional, metabolism
soft tissue

Question 21

Types of osteolytic lesions

Answer 21

geographic
motheaten
permeative

Question 22

Characteristics of geographic lesions

Answer 22

destructive, sharp borders, less aggressive, slow growing, benign, narrow zone of transition

Question 23

Characteristics of moth-eaten lesions

Answer 23

destructive, ragged borders, more rapid growth, may be malignant, 2-5 mm diameter

Question 24

Punched-out lesions are characteristic of what?

Answer 24

multiple myeloma

Question 25

characteristics of permeative lesions

Answer 25

ill-defined, worm holes, wide zone of transition, implies aggressive malignancy

Question 26

Osteoblastic lesions

Answer 26

aka osteogenic | refers to a lesion that produces new bone where it should not be

Question 27

A narrow zone of transition indicates what type of margin

Answer 27

sharp margins

Question 28

A wide zone of transition indicates what type of margin

Answer 28

poor margins | difficult to ascertain where the lesion starts and stops

Question 29

How does bone usually respond to lesions?

Answer 29

by making new bone

Question 30

What kind of periosteal response do you usually see with a slow growing lesion?

Answer 30

Solid the periosteum has plenty of time to respond to the process can produce new bone just as fast as the lesion is growing

Question 31

If a lesions grows quickly and unevenly, what type of periosteal response will you see?

Answer 31

lamellated aka onion skin | a pattern of one of more concentric rings of new bone over the lesion

Question 32

If a lesion grows quickly and evenly, what type of periosteal response will you see?

Answer 32

"sunburst" periosteum will not have time to lay down even a thin shell of bone, therefore the sharpey's fibers become stretched out perpendicular to the bone and ossify

Question 33

What will you see if the lesion grows too quickly for the periosteum to respond?

Answer 33

Codman's triangle only the edges of the raised periosteum will ossify forms a small angle with the surface of the bone, but not a complete triangle

Question 34

ddx for a solid periosteal response

Answer 34

benign, infection, or trauma

Question 35

ddx for a lamellated periosteal response

Answer 35

infection or primary malignant tumor

Question 36

ddx for a spiculated/sunburst periosteal response

Answer 36

very aggressive, primary malignant tumor

Question 37

ddx for codman's triangle

Answer 37

infection or primary mailgnant tumor

Question 38

What are the 5 radiographic densities in radiography

Answer 38

air, fat, water, bone, metal

Question 39

hounsfield unit

Answer 39

``` unit of radiographic density in CT gives the attenuation properties of a given tissue air = -1000 water = 0 bone = +1000 ```

Question 40

What is a bone window in CT?

Answer 40

differentiates medullary and cortical bone | soft tissue densities appear dark grey

Question 41

What is a soft tissue window in CT?

Answer 41

attenuation values of soft tissues | cannot differentiate cortical and medullary bone

Question 42

What is TR in MRI?

Answer 42

repetition time | time interval between the two 90 deg pulses

Question 43

What is TE in MRI?

Answer 43

the time between the pulse and the detection of the MR signal

Question 44

T1 MRI

Answer 44

short TR, short TE shows fat good for looking at bone marrow

Question 45

T2 MRI

Answer 45

long TR, Long TE shows water good for looking at organs, or bone for trauma

Question 46

Proton density MRI

Answer 46

long TR, short TE | all tissues

Question 47

Osteoporosis

Answer 47

most common metabolic disease of the bone resorption of the supporting trabeculae, spares the vertically oriented stress trabeculae decrease in quantity, not quality

Question 48

osteopenia

Answer 48

term used to describe general radiolucent bone | descriptive term, not a cause

Question 49

Principle compressive group

Answer 49

``` part of wards triangle runs from medial metaphyseal cortex to superior femoral head major weight-bearing trabeculae thickest, most densely packed last to be obliterated ```

Question 50

Secondary compressive group

Answer 50

part of wards triangle begins near the lesser trochanter, curves toward greater trochanter thin, widely separated

Question 51

Principle tensile group

Answer 51

part of wards triangle from the lateral cortex to inferior to the greater trochanter extends in an arch like pattern

Question 52

Wards triangle

Answer 52

confluence of three patterns, forms triangular radiolucency

Question 53

Insufficiency fracture

Answer 53

occurs when bone is not strong enough to withstand normal physiological stress